The treatment of malaligned teeth orthodontically involves the use of corrective mechanical forces applied over a period of time to move the teeth into proper orientation. The most frequently used devices are slotted brackets rigidly mounted on the teeth and a preflexed archwire which is placed in each slot and fastened. Under these conditions the spring pressure tending to return the wire to its original form is now exerted on each tooth as a corrective force. The result is a more desirable alignment of the teeth.
Archwires for the correcting of orthodontic problems are normally ligated to slotted brackets. The latter have previously been cemented to the teeth or, in an earlier process, soldered to bands which were then cemented around the teeth. Ligating is done with fine wires which are looped around "tie wings", small projections which are cast into each bracket. Although the method does hold the archwire securely, the handling of the fine ligation wires requires careful manipulation by the orthodontist and a considerable amount of chair time. The ties must also be removed and replaced each time that an orthodontic adjustment is made as the treatment progresses. The ligation wires constitute food traps (in addition to those produced by the archwires) and make the maintenance of hygienic mouth conditions more difficult.
A number of clamping brackets have been invented including those by Pletcher, U.S. Pat. No. 4,077,126 by Fujita, U.S. Pat. No. 4,355,975, and by Brader, U.S. Pat. No. 3,327,393. These devices, while eliminating the need for ligating wires, are themselves complicated and costly to manufacture in the small sizes needed in orthodontics. The brackets of Fujita and Brader utilize removable components which increase the danger of swallowing or inhalation spasms by the patient. In addition, these devices are unable to seat all of the various sizes of archwire into the base of their slots firmly, a condition necessary to maximize the tooth moving capability of the system.
It is an object of the present invention to provide an orthodontic bracket with no readily separable parts.
It is a second objective of the invention to provide a simple construction which permits relatively low cost fabrication.
It is a third and most important object of the invention to fully seat and lock various sizes and shapes of archwires and thereby maximize the tooth moving capability of the archwire system.
These and other objectives will become clear in the detailed description which follows.